package com.ning.springcloud.lb;


import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

@Component
public class MyLB implements LoadBalancer {
    //原子类
    private final AtomicInteger atomicInteger = new AtomicInteger(0);

    @Override
    public ServiceInstance instances(List<ServiceInstance> serviceInstances) {
        int index = getAndIncrement()%serviceInstances.size();

        return serviceInstances.get(index);
    }
    public final int getAndIncrement(){
        int current;
        int next;

        do{
            current = this.atomicInteger.get();
            next = current >= Integer.MAX_VALUE ? 0:current+1;
        }while (!this.atomicInteger.compareAndSet(current,next));
        System.out.println("****next:"+next);
        return next;
    }
}
